Over the centuries eiderdown has been coveted by the Vikings, Russian tsars and medieval tax collectors who accepted it as revenue. The plumage of a fat sea duck, eiderdown – treasured for its extraordinary lightness and insulation – now joins cocaine as an instrument of globalisation and commodity of the super-rich.

In this revelatory essay, Edward Posnett travels to the Westfjords region of Iceland to explore the fragile relationship between Icelanders and the duck. Eiderdown harvesting began with the arrival of Norse settlers in the 9th century, and it is now stuffed into pillows, duvets and clothing which sell for thousands of pounds in Japan, China, Germany and Russia. What might at first appear an idyllic pastime becomes a story of compromise and exploitation. Posnett’s finely spun prose and his fascinating encounters open up this seldom seen trade, one which hangs in the balance.